8 b Canadian Arctic Expedition, 1913-18 



Of the characters given by MacLeay, the following show the Caesirid 

 nature of his species. Semi-pellucid test, with viscera showing through; muscles 

 only (?) near apertures, and crossing at right angles and not obliquely, as in 

 Boltenia for example; branchial meshes irregular (as compared with Boltenia 

 and Dendrodoa); a renal organ— "diaphanous longitudinal pouch" containing 

 "two blackish nodules" — present and on right side; and left gonad above intest- 

 inal loop. Two characters given by MacLeay do not agree with those of Caesi- 

 rids. These are the 4-lobed oral aperture and the absence of a liver. In this 

 species the oral aperture has three lobes on each side, and of these the posterior 

 is the most prominent, after that the anterior, while the middle one is relatively 

 small. In a certain state of contraction, the middle lobe is distinguished with 

 difBculty, and the four atrial lobes are at the same time equally indistinct. 

 This is sufficient to explain MacLeay's description of the "branchial orifice" as 

 quadrified and the "anal orifice" "apparently without rays." While MacLeay 

 states that his species "has no liver very distinct," the structure that he described 

 and figures as the heart is doubtless the liver. The latter is well depicted 

 (although not named) in position, form, and shade, in his figure 4. 



In favour of the identification of MacLeay's species with C. crystallina, we 

 have the general shape, the size, the character of the surface, the presence and 

 character of the stalk, and the positions of the two apertures. Also the two 

 vascular processes (one is broken) which pass into the stalk, are represented 

 in his figure 4. He states, however, that "the branchial pouch has about fourteen 

 folds," whereas C. crystallina has been described as having only ten. The 

 condition of MacLeay's specimen apparently did not permit of accurate determ- 

 ination of the number. Nevertheless, in support of MacLeay's view as to 

 the indefiniteness of the number, we have in this species what appears to have 

 been overlooked, namely that there are in reality more than ten folds. In fact 

 there are fourteen rows of infundibula, and therefore fourteen folds. The 

 most dorsal and most ventral of the left side entirely lack longitudinal bars, 

 which renders them insignificant in comparison with the others, which possess 

 from three to four. On the right side the most ventral is without bar and the 

 most dorsal with one only. The formula of one specimen is: — 



Left. Dors. (0) (4) (4) (4) (3) (3) (0) Vent. 



Right. Dors. (1) (4) (4) (4) (4) (3) (0) Vent. 



Another point worth noting is that MacLeay refers to the branchial folds 

 being transverse in position rather than longitudinal, and this is indeed their 

 position. 



In view of these facts there can be no reasonable doubt as to the identity 

 of MacLeay's species. The name he has given must, therefore, replace Moller's 

 name chrystallina. 



The position of the testes in this species deserves consideration. Both 

 Van Name (1912, p. 495) and Oka (1914, p. 444) figure them as grouped along 

 the anterior half or two-thirds of the ovary. The latter also describes a new 

 species {Molgula redikorzevi) similar to this one, except that the testes are separ- 

 ated from the ovaries and lie, those of the right side below the renal organ, and 

 those of the left side in the intestinal loop, as in retortifotmis. Redikorzew 

 (1916) figures the testes in crystallina (p. 62) at the anterior end of each ovary, 

 and in redikorzevi (p. 67) on the right side from the anterior end of the ovary 

 around the anterior end of the renal organ and below it, and on the left side in, 

 below, and on the inner side of the intestinal loop. I have found that in one 

 large and nine small specimens from Bernard harbour, the testes are almost 

 invariably at or near the anterior end of the ovary, but tend to extend down in 

 front of the renal organ on the right and the intestinal loop on the left. In one 

 specimen on the left side they are on the outer side of the oviduct, that is at 



