18 University of California Publications in Zoology. [ VOL - 4 



grooves around the atrial opening appear to be without a counter- 

 part in any other species (fig. 21). It might be conjectured 

 that these are artifacts. Their regularity, however, and particu- 

 larly the sharpness of the grooves preclude, I believe, the possi- 

 bility of their being accounted for in this way when the firmness 

 of the test is considered. There is little doubt that they are 

 structural. Again C. pyramidalis seems to outdo all other species 

 in the great size and wide-openness of its atrial orifice. 



The one character of internal structure that seems to be 

 unique is the spicules. In other species these are spoken of as- 

 being calcareous. If they are actually of this nature in all other 

 cases, then pyramidalis stands alone in possessing spicules of 

 some other substance. What they are I do not know, but they 

 are unaffected by hydrochloric acid. 



There are three specimens of Cttlcolus in the collection, from 

 two stations, viz., 4394 and 4396, only a few miles apart. I am 

 not sure that all belong to the same species. Two of the speci- 

 mens, much smaller than the one here figured and described, 

 have some important peculiarities of their own. One has a sac- 

 culated stomach wall and in this particular resembles C. inurrayi 

 Herdman and C. thysonatus Sluiter. The number of specimens 

 is not sufficient to enable me to decide what the significance of 

 these diversities may be. I consequently prefer to leave the 

 matter for the present without an attempt to more definitely 

 assign the smaller individuals to their species. Since the animals 

 come from a great depth, over 2,000 fathoms, the question here 

 raised is of special interest, and it is greatly to be hoped that 

 more material may be secured before long. 



Station 4394, 32 54' N., 121 15' W. (just at the foot of the 

 continental slope west of San Diego), March 30, 1904, 2.259 

 fathoms, soft gray mud. Station 4396, 33 01' N., 121 32' W., 

 March 31, 1904, 2,228 fathoms, red mud. 



Microcosmus trans versus, n. sp. 



PI. 2, figs. 22 and 23. 



Superficial Characters. Cylindrical, axis transverse making 

 the orifices at nearly opposite ends; attached by less than middle 

 half of ventral side, the branchial end turning up somewhat more 



