NO. 12 ' A NEW HOLOTHURIAN DEICHMANN 3 



(3 mm. long) this inner layer is not yet developed. Feet with large 

 end plate, which is reduced in the papilliform feet on the dorsum; 

 the walls are filled with numerous supporting tables with a reticu- 

 lated spire composed of numerous rods and ending in numerous 

 branches or teeth. The introvert contains tables with a low spire and 

 numerous holes in the disk. The tentacles are packed with heavy per- 

 forated rods and plates ; toward the terminal branches the deposits 

 become smaller and more delicate, with larger holes. 



The color is mottled brownish, with black tentacles. 



The species is viviparous. 



Locality. — Magdalena Bay, west coast of Lower California ; inside 

 the northern point of the entrance to the bay, between Belcher Point 

 and the anchorage; 10-15 fathoms (18-27 m > sandy and weedy bot- 

 tom; July 18, 1938. Two specimens. (Type, U.S.N.M. no. E.5624 ; 

 cotype, U.S.N.M. no. E.5625.) 



Remarks. — The type is a female 15 mm. in length, with 13 embryos, 

 and the cotype is probably a male, to mm. long; both are well 

 expanded. 



The gonads are well developed in both specimens and consist of 2 

 tufts each with about 10 tubules. In the larger type the tubules are 

 short and some are almost empty- — one contains one large egg while 

 the others are more opaque. The oviduct appears to open into the 

 body cavity, near the stone canal. Thirteen embryos of varying age 

 were found lying free in the body cavity. The smallest embryo 

 measures 1 mm. in length and lacks all appendages except 5 cylin- 

 drical tentacles. The largest embryo measures 3 mm. and has 5 double 

 rows of tube feet and the full number of tentacles, which all are 

 branching as in a typical dendrochirote. The spicules in the smallest 

 embryo are of the usual juvenile type which occurs in almost all imma- 

 ture specimens — large plates regularly perforated by holes all of about 

 the same size. In the stages following, the typical spicules begin to 

 appear, although rather incompletely developed. In the oldest stages 

 the spicules are as in the mother animal, except that the layer of inner 

 buttons has not yet appeared. The color of the embryos ranges from 

 completely unpigmented white to mottled gray with numerous pigment 

 dots. 



The cotype has gonads with much longer tubules, with scattered 

 pigments spots. The tubules are opaque and appear to contain only 

 small cells, so it is probably a male. The opening of the gonadial duct 

 could not be traced with certainty ; probably it opens on the dorsal 

 side between the tentacles or closely behind them as in most 

 Dendrochirota. 



