The 7<latural History of the Frilled Shar\ 



313 



teeth in Carman's drawing are said to be ''six times nat." They measure 32.5 mm. ex' 

 actly, and in natural size must have been 5.4 mm. Careful measurements of the middle 

 cusp of the front teeth of our specimens give the following results: No. I (1350 mm. long) 

 has teeth varying from 4.5-5 mm.; No. II (1485 mm.), 4.5-5.5 mm.; No. Ill (1550 mm.), 

 4.5-5 mm.; the Columbia Univ. head, 4-4.45 mm. long. These measurements are ac' 

 curately made on perfect teeth (central cusps) in and around the symphysis of each jaw. 

 Many of these central teeth are broken, some with merely the fine points gone. Care has 

 been taken to avoid measuring these latter. There is here some variation, as is to be ex' 

 pected, and it is interesting to note that our largest specimen does not have the largest 

 teeth. Also it should be recorded that the teeth grow shorter progressively in the rows 

 approaching the corner of the jaws. Generally speaking, these front teeth average about 

 4.8 mm., or 0.6 mm. smaller than the size given by Carman for the central cusps of the 

 teeth of his fish, but 2.7 mm. smaller than the central cusp figured from one of the two 

 perfect teeth of C. lawleyi. 



CHLAMTDOSELACHUS TOBLERI FROM TRINIDAD ISLAND 



Some years prior to 1928, Aug. Tobler collected on the island of Trinidad and de- 

 posited in the Musee d'Histoire Naturelle of Basel, Switzerland, a curious three-pronged 

 fossil tooth. This was submitted to Maurice Leriche for study, and in 1929 he published 

 a short article in which he gave it the name Chlamydoselachus tohleri. 



This tooth was found in a calcareous marl, tuff-like in appearance and containing 

 Clobigerina remains, which had been ejected by the mud volcano Chagonary in the island 

 of Trinidad, Lesser Antilles. According to Leriche, the horizon is certainly Tertiary, 

 and more closely is either Oligocene or Miocene. 



This tooth, of which the central cusp is 6 mm. long, is figured in natural and twice 

 natural size. The half-tone screen was very coarse and the paper very soft, hence the 

 figure is very poor, showing everything without perspective. There is no modelling of 

 these teeth in the figures; both are shown as perfectly flat. We have had the figure care- 

 fully copied both in its natural size and in enlarged form, and reproduce these drawings 

 as our Text-figure 31. Contrasted with C lawleyi (Text-figure 30) the cusps are much 

 straighter, much heavier, more uniformly taper- 

 ing from base to tip, more sturdy in every respect. 

 However, the thing which most distinctly dif- 

 ferentiates tohleri from lawleyi is the presence of 

 a pair of long and slender secondary cusps on 

 either side of the central cusp. As already stated, 

 there are no secondary cusps in lawleyi. So far as 

 we can discern from Leriche's figures, in tohleri 

 all the cusps are practically straight, not curved 

 as in lawleyi and anguineus. 



Comparison of the tooth of C tohleri 



Text-figure 31 



A fossil tooth of Chlamydoselachus tohleri from 



the Tertiary of Trinidad Island: A (xl); 



B(X2). 



After Leriche, 1929. 



