1877.] 201 [Garman. 



responding to that occupied by the clasper of the male, they have the 

 rudiment of a similar organ, — a small cartilage articulated to the 

 basal, a little anterior to and separate from the other cartilages of 

 the fin. The proper analogue of the clitoris of higher vertebrates is 

 found in this rudiment. 



The pelvis of the species contained in the order ChimaeraB is in two 

 parts, very loosely joined by ligament. Each portion has, in the 

 males, articulated to it the cartilage of one of the pubic holders. 



The second order, Galeodes, shows an entirely different form of 

 this organ. It is in a single piece, bears no indication of a symphy- 

 sis, and has no other articulation than those of the ventrals in either 

 sex. It may be described as a transverse bar or shaft of cartilage, 

 placed across the belly immediately in advance of the vent. The 

 ilium is generally continuous with the balance of the shaft, which 

 from its shape and solidity offers little chance of distinguishing ele- 

 ments corresponding to those of the pelvis of higher animals. On. 

 the hinder side of each end of the shaft are the articulations of the 

 anterior and basal cartilages of the fins. 



The variations of the pelvis in shape and size are numerous in this 

 order, and may be used to advantage in determining the genera. In 

 great measure they can be correlated with the habits, and may be 

 stated in general terms as follows : an increase of strength, compara- 

 tive bulk and straightness in proportion as the habits of a genus 

 bring it more in contact with the sea bottom, and, conversely, an 

 increase in slenderness and curvature with decrease in size as the 

 dependence on the bottom is lessened. The greater resistance en- 

 countered by the body and in the use of the ventrals, from the sands 

 and impediments of the sea floor among those species making it their 

 home, determine the greater size and strength of this organ. 



A glance at typical genera selected from the order, as arranged 

 by Messrs. Muller and Henle, is sufficient to show the extent to 

 which reliance can be placed on the formula given above. Of the 

 genus Scyllium the pelvis is straight (on the front margin) and 

 strong; of Carcharias and Zygaina weak, depressed, and arched for- 

 ward ; of Mustelus and Triakis medium, not so much arched in front 

 as Zygaena; of Lamna arched forward, much depressed and weak; of 

 Odontaspis (the sand shark) like that of Scyllium, straight and 

 strong ; of Alopias depressed, short, arched forward and compara- 

 tively weak; of Cestracion (Port Jackson Shark) very stout, de- 

 pressed, sharp edged in front and straight, or with a slight backward 



