ASCIDIANS OF THE PHILIPPINES VAN NAME. 129 



but over considerable areas of the sac the internal longitudinal ves- 

 sels are perfect, at least in most specimens. These vessels are sep- 

 arated by from three to four stigmata, and number 40 to 50 on each 

 side of the body in fair-sized specimens. 



Stomach oval, perhaps with longitudinally corrugated walls, but 

 this is uncertain. Intestine of large diameter and forming a long 

 loop. 



Eeproductive organs situated beside the intestinal loop. Ovary 

 large, sac-like, containing a vast number of small eggs. Testes very 

 numerous. They are minute pear-shaped glands discharging by a 

 stout sinuous common sperm duct which accompanies the ascending 

 branch of the intestine. 



The above-mentioned group or colony of individuals (No. 38) is 

 from station D5168 (off Observation Island, Tawi Tawi Group, Sulu 

 Archipelago, Feb. 25, 1908, 80 fathoms, coral sand). 



The single zooids are from : 



No. 93. Station L5108 (off Corregidor Light, Jan. 15, 1908, 13 fathoms, 



coral) (Cat. No. 5936, U.S.N.M.). 

 No. 83. Station D5141 (off Jolo Light, Feb. 15, 1908, 29 fathoms, coral 



sand) (Cat. No. 5937, U.S.N.M.). 

 No. 37. Station D5174 (off Jolo Light, Mar. 15, 1908, 20 fathoms, coarse 



sand) (Cat. No. 5940, U.S.N.M.). 

 No. 34. Station 5555 (off Cabalian Point, Jolo Island, Sept. 18, 1909, 34 



fathoms, coarse sand) (Cat. No. 5941, U.S.N.M.). 

 No. 53. Station D5159 (off Tinakta Island, Feb. 21, 1908, 10 fathoms, coral 



sand). Two specimens (Cat. No. 5938, U.S.N.M.) 



The Philippine specimens are clearly of the species which has 

 commonly been known as R. fusca Herdman. It is common and 

 widely distributed in the Malay region and occurs on various kinds 

 of bottom and at various depths. The Siboga Expedition obtained it 

 from coral reefs and at depths down to 521 meters. According to 

 Sluiter (1904) its color when living is dark blue. 



The great variability exhibited by the Philippine specimens and 

 the apparent absence of any important structural differences between 

 the species lead the writer to the conclusion that the two species 

 R. crassa from the Ki Islands, 129 fathoms, and R. fusca from Banda, 

 Moluccas, 17 fathoms, collected by the Challenger Expedition and 

 described in Herdman's reports are identical, and that for the reason 

 above noted the name crassa should replace fusca. Herdman (1906, 

 p. 299, pi. 1, figs. 15-17) has described a species from Ceylon under 

 the name Ecteinascidia ( ? Rhopalopsis) solida, which appears to be 

 also so closely related to R. crassa that it ma}'' eventually require to 

 be united with it. 



101825°— Bull. 100—17 9 



