NARRATIVE OF THE CRUISE. 



105 



" In the Family Molgulidae, beyond the two gigantic pedunculated forms, destitute 

 both of hair-like processes from the test and incrusting sand, which have been placed 

 in the new genus Ascopera, no very striking novelties were discovered. In the 

 Ascidiidse, however, there are three noteworthy new genera — 

 Corynascidia, Abyssascidia, and Hypobythius, all from deep 

 water. Of the last, one species, Hypobythius calycodes, 

 was described by Mr. Moseley, 1 and a second, Hypo- 

 bythius moseleyi, agreeing with the first in the simple struc- 

 ture of the branchial sac, but differing in the body form and 

 some other details, was afterwards found in the collection. 

 Corynascidia suhmi (see fig. 68) is, like so many other of the 

 abyssal forms, supported upon a peduncle. The position and 

 course of the intestine are peculiar, 2 and the branchial sac is one 

 of the most beautiful and delicate known. The third genus, 

 Abyssascidia, is a connecting link between the well-known 

 genera Ascidia and Corella. It resembles the latter genus in 

 the position and especially in the course of the intestine, while 

 in the structure of the branchial sac it differs greatly from 

 Corella, and exhibits the simpler arrangement found in Ascidia, 

 from which again it differs in the condition of the dorsal lamina, 

 and in the large number of lobes surrounding the branchial and 

 atrial apertures. 



" A little group of three species, for which the new genus 

 Ecteinascidia has been founded, forms a connecting link be- 

 tween the previously known Clavelinidse and the Ascidiidse, 

 and shows that the group of Social Ascidians, established in 

 1828 by Milne-Edwards, must now be merged in the Ascidise 

 Simplices. 



"The geographical distribution of the Simple Ascidians 

 is very wide, but it appears from the Challenger investiga- 

 tions that they are not abundant in the northern hemi- 

 sphere, and are comparatively scarce in tropical latitudes, 

 while they attain 'their greatest numerical development in 

 southern temperate regions. The bathymetrical range is also fio. 68.— corynascidia suhmi, Heni- 



man. Seen from the right side, 



wide, extending from the littoral zone down to 2900 fathoms, natural size. 



Out of 82 species, 47 were found between the shore and 



50 fathoms, and only 7 at depths over 2000 fathoms. The tables given in the 



1 Moseley, Trans. Linn. Soc. Lond. (Zool.), ser. 2, vol. i p. 287, 18T7. 



2 See Report on the Tunicata, Part I., Zool. Chall. Exp., part xvii. p. 283. 



