90 
TH. MORTENSEN, 
(Schwed. Südpolar- Exp. 
Schizaster (Tripylaster) Philippii (Gray). 
PI. XII, Figs. 8, io — il. PL XIX, Figs. 5, 7, 15 — 16, 21, 31, 48 — 49. 
Tripylus Philippii Gray. 1851. Description of some new genera and species of Spatangidæ 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. 1. 
Schizaster — A. Agassiz. 1872 — 73. Revision of Echini, p. 158, 612. PI. XXVI, Figs. 40 — 41. 
— Studer. 1880. Übersicht d. »Gazelle» Echinoiden. Mon. Ber. d. Berlin Akad., p. 884. 
— Meissner. 1S96. 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. 
— Döderlein. 1906. Die Echinoiden d. deutschen Tiefsee-Exped., p. 252. Taf. L, Fig. 4. 
Schizaster ( Tripylaster ) Philippii Th. Mortensen. 1907. »Ingolf» Echinoidea II, p. 122, 123. 
Non: Schizaster Philippii A. Agassiz. 1904. Panamic Deep Sea Echini, pd 206. Figs. 297 a, 298. 
(These figures are reproduced from LovÉn’s »Etudes« PI. XI, Fig. 99, which represents Abattis 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 Brisaster fragilis , those on the posterior end of 
the actinal side do not form distinct tufts. 
The pedicellariæ 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 DÖDERLEIN (Op. cit.). 
A few additional remarks and also a few figures still seem to me not superfluous. 
— The globiferous pedicellariæ (PI. XIX Figs. 31, 48) are of the same structure as 
in Schizaster , with an interior glandular cavity. As stated by Döderlein 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 
