THIKD, OK \ i:i;.MKi:i:.\N BBJLNCH. I 1 1 



Caloceras laqucum, Htati 



>tlll. hi. 1-1 \ I I I 



Amm. laqwi. 



Am". ' ,17. 



\iiiiii . p 81 • 

 H . .ii i. Ibid., p -ili, pi. x\ : 



7. - 

 Amm. Scy. .ites. 



The youngest specimen I have yet Been of this Bpecies was 26 mm. in 

 diameter. The abdomen, however, was Bmooth, with no indications <>l" the 

 immature keel of the adult, the sides exceedingly jril>l»»n<. The pilaa evidently 

 •i early, and were closely crowded and Blightly curved forwards. 

 In one specimen the pilae were verj Blightly developed in the adult; in 

 another, al :i corresponding size, they were already disappearing, and upon the 

 •lilc whorl they were almost obsolete. The keel probablj becomes 

 slight .it tlii- time, and the likeness to its own young must then have 

 i remarkably close. 1 This specimen was ~> : > mm. in diameter. 

 The similarity of the adult of tin- Bpecies to the young "i Ver. spiratissimum 

 is unmistakable. A specimen from Bebenbausen, in Quenstedt's collection, shows 

 that the Butures are intermediate between those <>!' ' J ! those of 



1 In- young of s specimen from Oestringen in Praas's collec- 

 tion, Stuttgardt Museum, when about 26 nun. in diameter, has the exact form 

 and charai I dt's figure, but no Bigns of a keel, though tlii- appears 



ifterwards. A fine series in the Semur Museum shows that the k < •« -1 may 

 et have arisen in a specimen at the diameter of 15 mm. The whorl also 

 ut the time of the appearance <>i the keel may have either a broad, depi 

 abdomen, as in the varieties which approximate to the young of Ver. sptratUsi- 

 , or tlii< part may be elevated, a< in ('ill. tortile. 

 Tin' young, however, are lik<- the young of Cul. Johmtoni. The sutures also 

 vary in the same way, some specimens having Butures like those otJo/uuti 

 others approximate t<> tho m. (ml age in all these 



irked bj narrowing "t the abdomen, loss of the keel, etc, which probably 

 ling off of the same region, though this extreme • i nility 



not observed. The pilaa often cross the abdomen in the young, but not 

 in the adult. In oi len, however, which had the Benile angularity of 



ibdomen well marked al the diameter "i 7". mm., the pilse again en 

 the abdomen, and then faded out almost entirely Another specimen, even at 

 imeter of 106 mm., retained a keel, as in tli<' adult. 

 ./ B Wiiu'lit. from the Angulatus bed, may be an example of this 



It exhibits 1 1 1 • - - i quadragonal form <>f tl and is not, 



I -imilar tu an if the first I 



t. from the lower part <>!' the Angulatus \»-<], probably also belongs t" 



i 



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