NO. 1989. A8CIDIANS FROM NORTHEASTERN PACIFIC— RITTER. 465 



gonads given in the diagnosis will almost certainly have to be modi- 

 fied when fuller knowledge is obtained. The masses called testes in 

 the text and figures contain ova as well as sperm, and since these are 

 both small and large they are obviously produced here. In other 

 words the gonads are hermaphroditic in the sense in which this 

 condition prevails with many ascidians. So far no unusual difficulty 

 appears. The puzzle is as to the nature of the cylindrical body 

 called ovary in the description. This contains ova in most of its 

 length, these being in part large, apparently ripe, and in part small 

 and immature. They cling to the inner wall of the canal forming 

 a definite layer thereon, but show no true ovarian arrangement. 

 The exact relation of these to the gonad lobes can not be made out 

 owing to rupture and disarrangement of the parts. From what can 

 be observed the cylinders would seem to be receptacles which receive 

 the ova from the ovaries while still immature, and in which they 

 ripen. 



In external appearance this species considerably resembles C. 

 wyviUe-tliomsoni Herdman, though the body of sluiteri is somewhat 

 longer proportionately and is more regular, the prominences on the 

 test being here somewhat smaller and uniformly distributed. Per- 

 haps the most distinctive feature about sluiteri is the small number, 

 5, of branchial folds, 6 being the prevailing number in the genus, 

 though one species, C. gigas Sluiter has 7 folds. But it should be 

 stated that intimations of folds occur at several places between the 

 large, well-defined folds in C. sluiteri. Another feature, the absence 

 of spicules from the tissues of the internal organs, would be, should 

 it prove on further study to be true for all individuals and in all 

 conditions of life, the most considerable differential mark of the 

 species, and might even be considered sufficiently important to entitle 

 sluiteri to be taken as the type of a distinct genus. Until, however, 

 more specimens have been examined, and until we know more than 

 we now do about the physiological significance of mineral deposits in 

 the tissues of ascidians, I do not believe it is wise to place great 

 emphasis on their value in classification. It is possible, too, that the 

 much elongated ovaries and the sharp separateness of these from 

 the testes may some time serve as characters of generic rank. 



I am glad to name this well-marked, interesting species after 

 Doctor Sluiter who has added so materially to oar knowledge of the 

 genus. 



Type-locality. — A single specimen. Albatross station 3480, lat. 52° 

 06' N.; long. 171° 45' (just south of Aleutian Islands), 283 fathoms, 

 bottom bk. s. co. rky., July 8, 1893. 



r^pe.— Cat. No. 5688, U.S.N.M. 



80459°— Proc.N:M.vol.45— ft 30 



