265 



tentacles, each with four digits. The tentacles measure ca. 3 mm 

 in length. Sensory cups are never mentioned. Britten writes 

 that the calcareous ring consists of "12 fast gleichförmigen Stücken" 

 with the posterior margin waved, but whether the radiais are per- 

 forated or not is not mentioned. There is one polian vesicle and 

 a short and twined stone-canal. The intestine has no loop, and in 

 the specimens at hand it is very folded. The gonads are long, thin 

 and branched. The ciliated funnels (Fig. 49. 3) are found on the 

 body-wall. They are rather like the funnels in Leptosynapta inhaerens 

 (O. F. Müller) and measure 150 — 200 // in length. 



The anchors (Fig. 49. 1) are rather small and very irregular in 

 shape. They measure 86 — 140 fi in length and may often be wider 

 than long. They are usually faintly hollowed or flat on the vertex, 

 and on the arms there may be one to two large teeth. The anchor- 

 plates (Fig. 49. 2) are as the anchors of very varying shape, but 

 they are usually square or quadrangular. They measure 70 — 120/^ 

 in length and usually very nearly the same in width. They are 

 irregularly perforated with smooth holes and the articulation with 

 the anchors may be nearly warning. 



There are three different sorts of miliary granules in the spec- 

 imens at hand. The first, the most characteristic, was discovered 

 by v. Marenzell er. It is small, perforated plates, more or less 

 developed. When fully developed (Fig. 49. 6) they are rather bowel- 

 shaped with an undulating edge. The second (Fig. 49. 5) was found 

 by Oh shim a, who in "The Synaptidae of Japan" mentions some 

 "smooth, oval granules, 20 fi in diameter" found deeply imbedded 

 in the radii. The third sort found in the specimens at hand (Fig. 

 49. 4) are rounded or oval rods, measuring 30 —35 fi in length. 

 They are found scattered among the small perforated plates in the 

 interambulacra. 



Protankyra autopista is, though it is easily distinguishable from 

 all the other species of the genus, a much discussed species. Théel 

 suggests that it may be referred to molesta Semper, and Clark 

 writes in "The Apod. Holoth." that "it may be that the type and 

 only known specimen is simply the anterior part of the body of a 

 peculiar individual of the preceding species" (i. e. bidentata Wood- 

 ward & Barrett). That these suggestions are erroneous, and that 

 autopista is a valid species distinctly different from bidentata, was 

 shown by Ohshima in "The Synaptidae of Japan". 



