go 



TH. MORTENSEN, 



(Schwed. Sudpolar-Exp. 



Schizaster (Tripylaster) Philippii (Gray). 



PI. XII, Figs. 8, io— II. PI. XIX, Figs. 5, 7, 15—16, 21, 31, 48—49. 



Tripylus Philippii Gray. 1851. Description of some new genera and species of Spatangidte in the British 

 Museum. Ann. Mag. Nat. Hist. 2 Ser. VII, p. 132. 



— ■ — Gray. 1855. Catalogue of the Recent Echinida of the Brit. Museum. I. Echinida 



Irregularia, p. 59. PI. V. I. 

 Schizaster — A. Agassiz. 1872 — 73. Revision of Echini, p. 158, 612. PI. XXVI, Figs. 40 — 41. 



— — Studer. 1880. Ubersicht d. »Gazelle» Echinoiden. Mon. Ber. d. Berlin Akad., p. 884. 



— — Meissner. 1896. Die von Dr. Plate aus Chile heimgebrachten Seeigel. Arch. f. Natur- 



gesch. I, p. 89. 



— — Meissner. 1900. Die Echinoiden d. Hamburger Magalh. Sammelreise, p. 15. 



— — Doderlein. 1906. Die Echinoiden d. deutschen Tiefsee-Exped., p. 252. Taf. L, Fig. 4. 

 Schizaster {Tripylaster) Philippii Th. Mortensen 1 . 1907. *Ingolf» Echinoidea II, p. 122, 123. 



Non: Schizaster Philippii A. Agassiz. 1904. Panamic Deep Sea Echini, p." 206. Figs. 297 a, 298. 

 (These figures are reproduced from Loven's »Etudes< PI. XI, Fig. 99, which represents Abatus Phi- 

 lippii Lov. and has nothing to do with Schizaster Philippii Gray.) 



Some other less important literary references are given in the papers quoted by 

 Dr. Meissner. 



To the previous descriptions the following remarks should be added. 



The abactinal side of the test is gently sloping from the middle towards both 

 ends. The actinal plastron is somewhat arched. The posterior prolongation of the 

 labrum is short, ending off the first adjoining ambulacral plate. The interporiferous 

 space of the odd ambulacrum is stated by AGASSIZ to be >quite narrow*, which 

 cannot be said very appropriately; the pores are placed close to the edges of the 

 ambulacrum. The tubefeet of the anterior ambulacrum have a well developed sucking 

 disk with rather long rosette plates. There are four well developed subanal tube- 

 feet, the first of them occurring on the 7th ambulacral plate. The spicules of the 

 tubefeet are not very numerous, small, irregular, branched rods. The latero-anal 

 fasciole passes over the 12th plate of the posterior ambulacra. The spines are upon 

 the whole short and fine, as in Brisastcr fragilis, those on the posterior end of 

 the actinal side do not form distinct tufts. 



The pedicellariae are of the globiferous, rostrate, tridentate and triphyllous types. 

 The tridentate and rostrate have been figured by AGASSIZ in »Revision of Echini* PI. 

 XXVI, Figs. 40—41, while all four types have been figured by DODERLEIN (Op. cit). 

 A few additional remarks and also a few figures still seem to me not superfluous. 

 — The globiferous pedicellarias (PI. XIX Figs. 31, 48) are of the same structure as 

 in Schizaster, with an interior glandular cavity. As stated by DODERLEIN the ter- 

 minal opening is surrounded by 3—4 teeth; generally there are four, but sometimes 

 there may even be only the two. The basal part is rather narrow, the sides some- 

 what reenteringly curved. The muscles from the head are fastened on a little 

 swelling some distance below the upper end of the stalk; the thick skin covering 

 the valves continues some way down on the stalk (PI. XIX Fig. 48). The rostrate 



