PACIFIC TUNICATA OF U.S. NATIONAL MUSEUM 129 



57. Distaplia inikropnoa (Sluiter) 



FlGtJBE 46 



Polyclinum mikropnous Sluiter, 1909, p. 94, pi. 5, fig. 1. 

 Distaplia inikropnoa Tokioka, 195.5b, p. 51, fig. 2 ; pi. 5, figs. 11-16. 



MATERIAL EXAMINED 



Pat.att Islands: 1% mi. NE. of Ngabadangel ("Gabadaguru") ; GVF sta. 12.5. 

 Five colonies (USNM 11436) and one small colony (USNM 11437). 



Description. — Six colonies are in the material from the Palau 

 Islands. They are all fungiform, consisting of a roimdish or ovoid 

 corona containing zooids within, and a peduncular portion including 

 fascicular vessels, and is attached to fragments of reef corals by the 

 basal end of the peduncular portion. The largest colony is 33 mm. 

 in length, the upper half of the colony is occupied by corona; the 

 peduncle is thinner than the corona, the diameter may be less than 

 half of that of the corona. 



Coronal test gelatinous, transparent, yellowish white or dark brown- 

 ish, very soft in consistency ; rarely carries a small amount of fine sand 

 grains or mud on the surface, or within the test. Peduncular test 

 rather hard, translucent, pale brownish; surface generally exposed 

 although small sponges or ^gg masses of some invertebrates are some- 

 times attached. Although system of zooid arrangement is obscure, 

 with some difficulty it is found to be somewhat like that in Sycozoa. 

 In larger coronae, zooids arranged roughly in paired longitudinal 

 rows, up to 9 pairs in examined colonies. About 10 mature zooids in 

 each of paired rows, arranged in zigzag-fashion. Some minute oval 

 bodies in test of peduncle, usually quite structureless; probably ves- 

 tiges of buried fecal pellets. 



Zooids 2 mm. to 5 mm. in length excluding postabdomen. Abdo- 

 men situated nearly perpendicularly, li/^ times as long as contracted 

 thorax, Postabdomen is shorter than abdomen, usually less than two- 

 thirds of length of abdomen ; issues from right posterodorsal part of 

 abdomen. Branchial aperture faintly cut into 6 lobes, atrial aper- 

 ture a huge opening with well-developed atrial languet. About 

 15 longitudinal muscles on each side of thorax. Approximately a 

 dozen stigmata in each of four rows. Parastigmatic vessels not found 

 in any examined zooids. Larger tentacles 6, also smaller ones ; dorsal 

 languets very long and slightly displaced to left side from dorsomedian 

 line. Ciliated groove a minute oval opening. Neck region of abdo- 

 men rather short, stomach situated in anterior half of abdomen. Sur- 

 face of stomach marked with about 20 longitudinal plications; in some 

 zooids surface looks quite smooth, but longitudinal plications of inner 

 wall can be seen clearly. Hind stomach distinct, while midintestinal 

 portion obscure in many zooids or defined A^ery faintly in some. In 

 latter case, short midintestine separable from following rectum by 

 slight lateral depressions at level A shown in figure 46/0 and colored 



