232 W. HAROLD LEIGH-SHARPE 



an enormous bag. The deep pouch into which the apopyle 

 leads is actually the wide mouth of the posterior end of this bag, 

 so that no siphon tube is developed. 



RHINOCHIMAERA ATLANTICA 



It is stated that the males of Harriotta, a deep-sea member 

 of the Holocephali, which this species closely resembles, have 

 hitherto only been described from immature specimens. The 

 following account of Rhinochimaera is made from a mature 

 specimen, 84 cm. in length, taken off the southwest of Ireland in 

 1910. 



In all its details Rhinochimaera shows a close similarity to 

 Chimaera monstrosa (Memoir IV, p. 201), except that the clasp- 

 ers, instead of being bifurcated into external and internal radii 

 as in Chimaera, are single, resembling the more slender of the 

 radii of the other genus. 



Rhinochimaera agrees with Chimaera in the following points 

 (fig. 13) : The pelvic fins are of the same conformation and cover 

 over the claspers so as to conceal them. Leading into the apo- 

 pyle is a cavity similar and similarly situated to that of Chimaera, 

 which has already been described at considerable length. An- 

 terior claspers are present, which can be retracted into a slit-like 

 pouch, thus the clasper on the (observer's) left is almost fully 

 protmded, while that on the right is aknost withdrawn. The 

 clasper is almost entirely composed of cartilage, but instead of 

 being serrated on its morphological inner border it is beset with 

 booklets, hke those of the pelvic claspers, which serve the same 

 function as a serration. The histological details are the same, as 

 far as I have been able to examine them. The clasper pouch, 

 however, is set obliquely to the animal's axis (transverse in 

 Chimaera, longitudinal in Callorhynchus), and the clasper is 

 not spoon-shaped. 



On account of its prolonged rostrum, inter alia, Harriotta has 

 already been classified as showing affinities with the fossil Squa- 

 loraja polyspondyla, rather than with Chimaera; so also should 

 Rhinochimaera. And, in the organs we are considering, there 

 is another close resemblance, for the dehcate, very flexible, 

 posterior claspers, instead of being freely denticled, terminate in 



