NO. 3 DEICHIMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 119 



Remarks. — The diagnosis is based on the type of glasselli, a single 

 adult individual. More material is needed, especially of younger individ- 

 uals, to complete the diagnosis. The genus is not related to any other form 

 known from the Panamic region. From the w^est coast of North America 

 a form with somewhat similar spicules is known, Thyone benti Deich- 

 mann, including a variety, var. zacae, from off Cerros Island, Lower Cal- 

 ifornia, but that species has a taller, more delicate calcareous ring, 

 exceedingly small tentacles, and larger spicules. 



Athyone glasselli (Deichmann) 



Thyone glasselli Deichmann, 1936, p. 63, text figure 1 ; 1937, p. 170, text 

 figure 2. (Comparison with T. benti.) 



Diagnosis. — As for the genus. Color brownish. Resembles superficially 

 Thyone briareus (Lesueur) from the coast of North America. Shallow- 

 water form. 



Type.— M.C.Z., cat. no. 736. 



Type locality. — Punta Penasco, Sonora, Mexico. 



Distribution. — Known only from the type locality. 



Depth. — Shore, buried in sand. 



Specimens examined. — The type. 



Remarks. — The strongly contorted type specimen must have meas- 

 ured more than 10 cm. in expanded, normal condition. More material is 

 necessary to explain from what type of spicules the buttons and rods are 

 derived. Very likely younger individuals may have distinct spire on the 

 buttons and the supporting rods and thus be derived from tables. 



The species is not closely related to any other species known from the 

 Panamic region. Thyone benti, from Puget Sound, and var. zacae from 

 Cerros Island have similar spicules but much larger and definitely derived 

 from tables; the calcareous ring is much more tubular and more delicate 

 and the tentacles are unusually small. From the southern part of South 

 America Thyone lechleri Lampert is known to have similar swollen but- 

 tons, but the calcareous ring is entirely different with no posterior pro- 

 longations at all. 



The only other soft-skinned Thyone with few spicules described from 

 the Panamic region is the dubious Anaperus peruana Troschel, possibly 

 identical with Lesson's species (see discussion, p. 120). 



Regarding Thyone ovulum Selenka, which Deichmann (1936, p. 65) 

 mentioned as possibly the juvenile stage of A. peruana, the type has been 

 re-examined and found to be a phyllophorid (see p. 125). 



