-22—
to strongly projected at their ventral ends and ending in tubercles or
'swellings!. All are compressed wa hove a ae a sulcus of easel: de th.
A peculisr devarture from tyxical Parstrachyceras is shown by the
soecimen figured by arthaber (1915) as P. suigiisatetnnn from the late Ladinian
of Bithynia. It has «= very shallow sulcus and the ribs instead of ending in
tubercles or svellings on the border of the ventral sulcus continue across it

without interruotion,.

Paratrachyceras sutherlandi n. SD.
(Plate V, figure 9)
This species is briefly described in the printed appendix. It resemoles
the specimen from Bithynia figured by Arthaber (ROT ei eraeeuerersene oe
Paratrachyceras regoledanum Mojsisovics; it has the same shall ow rertred

sulcus and the ribbing similarly crqsses this sulcus, but the ribbing is

-Coarsger and the suture line simpler.

Paratrachycoras aylardi n. sp.-
(Plate VIII, figures 1,2)

Two soecies Paratrachyceras caurinum n. sp. and 'P. aylardi n. sp. differ
considerably from P. sutherlandi, having somewh:.t the aopearance of an |
Arpadites but lacking the keels marginal to the ventral sulcus. They are not
quite tyoical Paratrachyceras, as they lack the definite ventral tubercles or
swellings of the ventral ends of the ribs. The ribs are attenuated on’ the
ventral shoulder, and exhibit a slight tendency to enlarge a little at their
ventral énis. Some species of Sirenites show this attenuation of ribs on the
ventro-lateral shoulder. These species are closest to the more evolute late
Ladinian species of Paratrachyceras, for example the late Ladinian species
Paratrachyceras richthofeni Mojsisovics. The suture line is poorly vreserved,

but is known to be simole and apparently weakly ceratitic. They are tentatively

included in Paratrachyceras .

bavstradnyceres aylardin. sp. is briefly described in the printed
appendix. It-is fairly evolute, somewhat compressed. The wrorls are much
aslatiae Gee. thick, have flattened sides, rounded ventro—lateral shoulders,
ventral sulcus, no keels and well-rounded umbilical shoulder. ‘The sides of
the whorl are ornamented with fairly coarse ribs, strongly projected and also

attenuated on the ventro-lateral shoulder; some ribs are single, some divide

closé to the umbilicus, others high up on the sides. The ventral ends of