DESCRIPTION OF SPECIES 127 



Occurrence. St. 1686: Victoria, Australia, o m. 



External appearance. The single specimen measures 1 1 cm. long by 7 cm. high, and is heavily 

 encrusted with hydroids and other organisms. The short wide siphons are visible externally. 



Internal structure. As the species has been described in detail by several authors (see particularly 

 van Name, 1945 ; Kott, 1952 ; and Tokioka, 1953) I shall mention only a few important features of this 

 specimen. 



Dorsal tubercle. The tubercle is a large conspicuous cushion with a complicated sinuous slit 

 (Text-fig. 52 A), similar to that illustrated by Kott (1952, fig. 124), for var. grandis. 



Branchial sac. There are fourteen folds on one side of the branchial sac, with up to thirty longi- 

 tudinal bars on the larger folds, and several between folds. 



Text-fig. 52. Herdmania momus (Savigny) (St. 1686): A, dorsal tubercle; B, anus. 



Gut. About twenty-four lobes surround the anal opening (Text-fig. 52 B). 



Remarks. This is a very variable species, but is always readily identified by the spicules in the body 

 wall and branchial sac, and by the large number of branchial folds. 



Several varieties and forms (see Michaelsen, 1919; Kott, 1952) have been described and for a dis- 

 cussion of these van Name (1945) and Tokioka (1953) should be consulted. Both of these latter 

 authors suggest that the subdivisions of the species have little systematic value, but nothing can be 

 added to the argument here on evidence from one specimen. This specimen agrees closely with the 

 description of var. grandis, which is characterized specially by (1) the large size, (2) the large number of 

 branchial folds (ten to thirteen on each side), and (3) the large and complex dorsal tubercle. 



Distribution. Widely spread in warm waters of the world. 



Genus Bathypera Michaelsen, 1904 



Bathypera splendens Michaelsen (Text-fig. 53) 



Bathypera splendens Michaelsen, 1904, p. 192, pi. 10, fig. 9; pi. 11, figs. 15-19. 

 Pyura Kouvillia Sluiter, 1912, p.. 543 



Occurrence. St. 181: Palmer Archipelago, 160-335 m - 



External appearance. The body of the single specimen is roughly spherical, approximately 2 cm. 

 in diameter and slightly flattened on the dorsal side, where the siphons make two small, widely 

 separated, conical projections. The general colour is grey, paler on the siphons, and the surface feels 

 rough to the touch owing to the presence of the characteristic test spicules (Text-fig. 53 A) arranged 

 at right angles to the surface. 



Internal structure. Several detailed descriptions (Michaelsen, 1904 ; Hartmeyer, 191 1 ; Herdman, 

 1923; Kott, 1954) leave little to be added. In the 'Discovery' specimen the dorsal tubercle has a 

 complete C-shaped slit (Text-fig. 53 B), not broken into two parts as in Kott's description. Michaelsen 

 described and illustrated a short oviduct and sperm duct, but in Kott's specimens these were much 

 longer. The present specimen shows only moderately long ducts. 



Distribution. Antarctic (Graham Land, Enderby Land, Kaiser Wilhelm II Land, Adelie Land, 

 Wilkes Land, MacRobertson Land). 



