PART 5 A MONOGRAPH OF THE EXISTING CRENOIDS 761 



Syzygies occur between brachials 3+4, 9 + 10, and 14 + 15, and distally at intervals 

 of 3 muscular articulations. 



PI is 7 mm. long with 15 segments, of which the first and second are short, the 

 third is from two to two and a half times as long as broad, and those following are 

 from three to four times as long as broad. P 2 is 4 ram. long with 8 segments, of which 

 the third or fourth to seventh bear a gonad. PS is 4.5 mm. long with 9 segments, bear- 

 ing a gonad on the third to seventh; the distal segments are a little spin} 7 distally. 

 The distal pinnules are from 6 to 7 mm. long with about 16 segments. 



Doctor Gislen also assigned to T. comaster another very young specimen from 

 Sagami Bay in 274 meters. The centrodorsal is low and flattened, almost hidden by 

 the cirri, which are about XXVI, 7-10, from 2 to 3 mm. long, arranged in 2 rows. 

 The second cirrus segment is three-quarters again as long as broad, and those following 

 are four times as long as broad, and expanded distally; the antepenultimate segment 

 is three-quarters again as long as broad, and the penultimate is as long as broad with 

 an indistinct opposing spine. 



The IBr! are three times as broad as long; the axillaries are a third broader than 

 long, the posterior process about twice as long as the distal angle. The 10 arms are 10 + 

 mm. long. The first brachials are almost free anteriorly, the second brachials have a 

 posterior process. PI is 1.8 mm. in length with about 10 segments which are two and 

 a half times as long as broad. There is a gap between P t and the distal pinnules. The 

 disk is 1.3 mm. in diameter. The anal cone is 1 mm. high, narrowly sausage-shaped. 



Localities. -Albatross station 3697; Sagami Bay, Japan; Manazuru Zaki bearing 

 N. 26 W., 6.0 miles distant; 219-484 meters; gray mud and volcanic sand; May 5, 1900 

 [A. H. Clark, 1908] (1, U.S.N.M., 22694). Type locality. 



Challenger station 236; off Sagami Bay, Japan (lat. 3458' N., long. 13929' E.); 

 1417 meters; temperature 3.11 C.; green mud; June 5, 1875 [von Graff, 1887; P. H. 

 Carpenter, 1SSS; A. H. Clark, 1913] (3, B.M.). 



Dr. Sixten Bock's station 4, Misaki, Sagami Bay, Japan; on the "Melacrinus 

 shoal"; 274 meters; May 5, 1914 [Gislen, 1922] (1, Stockholm M.). 



Dr. Sixten Bock's station 37; Okinose, Sagami Bay; 731 meters; July 8, 1914 

 [Gislen, 1922] (1, Stockholm M.). 



Geographical distribution. This species is only known from the vicinity of Sagami 

 Bay, near Tokyo, on the southeast coast of Japan. 



Bathymetrical distribution. From 274 (?219) to 1417 meters. 



History [by A.M.C.]. The first mention of this species is by von Graff (1887), 

 who gave Antedon alternata as the host of a myzostome (Myzostomum cornutum) from 

 Challenger station 236. 



In the following year Carpenter described alternata but mainly from specimens 

 taken near New Zealand which Mr. Clark later found to be distinct and, accordingly, 

 in 1913 provided the new name cypris for the specimens from Challenger station 236. 

 However, in 1908 he had described a new species, Thaumatometra parva, from a speci- 

 men taken by the Albatross also in Sagami Bay, which description has proved to be 

 indistinguishable from a newly drawn up one of the largest syntype of T. cypris. 



The only other records for the species are those of- two specimens collected by 

 Dr. Sixten Bock in Sagami Bay named T. comaster by Gisl6n in 1922, but it is not 

 inconceivable that the specimen from the Sagami Sea in 110 meters which Gislen (1927) 

 named T. cf. tennis (under which heading it is described here) is also referable to parva. 



