86 MR. G. C. CRICK ON THE MUSCULAR ATTACHMENT OP THE 



1'5 mm. wide for a lengtli of about 8'5 mm. ; it then expands somewhat rapidly to a 

 width of 4'5 mm., a width which it maintains across the rest of the body-chamber, 

 joiniog the band on the opposite side, the portion near tlie periphery being, however, 

 somewhat less distinct than the rest. 



The discrepancy in the position of the two impressions is doubtless due in a great 

 measure, if not entirely, to the crushing which the specimen has undergone during 

 fossilization. 



Amaltheus, Montfort. 



Amaltheus spinatus, Bruguiere, sp. — The muscular impression has been observed in 

 an example of this species in the British Museum Collection (No. C. ''919), the locality of 

 which is not recorded. The specimen consists of the well-preserved septate portion of the 

 shell, together with a natural cast of one side of the dorsal (or inuer) part of the posterior 

 portion of the body- chamber (PI. 18. fig. 7). The dimensions of the sjieciraenat the base 

 of the body-chamber are : — diameter of the shell 57 mm. ; width of umbilicus 24 mm. ; 

 height of outer whorl 19 mm. ; ditto above preceding whorl about 17 mm. ; thickness of 

 outer whorl (excluding ribs) 19 mm. ; ditto (including ribs) 22 mm. A portion only of 

 the anterior boundary of the muscular impression is preserved. Tliis, Avhich appears as 

 an impressed line, arises almost close to the suture (of the shell) 9 mm. in front of the 

 anterior part of the small saddle belonging to the last suture-line that is situated on 

 the edge of the umbilicus ; it curves outward and backward for a distance of about 5 mm. 

 where it is about 4 mm. from the suture (of the shell) ; then, passing backward nearly 

 parallel to the inner edge of the whoid, it appears to divide just before meeting this 

 small saddle, one part passing on the inner (dorsal) side of the small saddle situated on 

 the edge of the umbilicus and then disappearing, the other passing on the outer side of 

 the same saddle and then also disappearing. Posterior to this distinctly-impressed line 

 there are several very faint lines coacenti'ic with it. 



Cardioceras, Neumayr & Uhlig. 



Cardioceras excavatum, J. Sowerby, sp. — In the description of the annulus, which 

 has already been given, I have described the muscular attachment in an example of 

 this species (see ante, p. 75). 



Another example of this species is also figured which shows the course of the anterior 

 l)0imdary of the muscular scar on the dorsal or impressed portion of the whorl (Pi. 19. 

 figs. 1, 2). 



Cardioceras aff. excacato, J. Sowerby, sp. — The muscular impression is also shown in 

 an example of Canlioccras in tlie Britisli Museum Collection (No. 50098), but its 

 locality is not recorded (PI. 18. figs. 9, 10). It is, however, allied to Card, excavatum, 

 but is more comjiressed and more widely umbilicated than that species. The dimensions 

 of the specimen are : — diameter of shell 54 mm. ; width of umbilicus 18'5 mm. ; height 

 of outer whorl 20 mm. : thickness of outer whorl 12 mm. The test has been removed 



