52 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I44 



Genus ASTROLAMPAS Pomel 



Astrolampas Pomel, 1883. Class, meth., p. 63. Type species by original desig- 

 nation, Pygurus produchis L. Agassiz. 



GENERIC DESCRIPTION 



Test medium to large, very low, elongate; apical system anterior, 

 tetrabasal ; petals long, broad, slightly closed distally, interporiferous 

 zones much wider than poriferous, petaloid pores conjugate, outer 

 pore slitlike, all ambulacral plates double pored ; periproct infra- 

 marginal, located three-quarters distance from peristome to posterior 

 margin ; peristome anterior, pentagonal ; bourrelets slightly developed, 

 not inflated; phyllodes long, narrow, double pored, with two series 

 of pore pairs in each half-ambulacrum ; no buccal pores ; tubercles 

 adorally slightly larger than adapically. 



Comparison zvith other genera. — Mortensen (1948, p. 135) stated 

 that if the apical system of Astrolampas prodiictus should be found 

 to be tetrabasal, the genus should be considered a synonym of 

 Py gurus. I have studied the apical system of the holotype of A. 

 productus and the apical system is tetrabasal, but I do not agree that 

 the genus should be considered a synonym of Pygurus. In A. pro- 

 ductus the bourrelets are not inflated and the phyllodes are narrow 

 with two series of pore pairs, with the inner series widely separated 

 from the outer. In Pygurus the bourrelets are strongly inflated, the 

 pore series in a half -ambulacrum in the phyllodes are always close 

 together, and in all the post-Callovian species the phyllodes are 

 greatly widened. 



Astrolampas is similar to Pygorhynchus in petal arrangement and 

 bourrelet development, but differs in having a flatter test, a more an- 

 terior periproct, and in general narrower and much longer phyllodes. 



Remarks. — Lambert and Thiery (1921, p. 357) refers seven spe- 

 cies to this genus, but two of them, Lambert's Astrolampas romani 

 and Cotteau's Botriopygus coquandi, should be referred to other 

 genera. I studied a topotype specimen of A. romani in the U. S. 

 National Museum. Lambert (1904, p. 841) did not figure the adoral 

 surface of his species, but the periproct is too near the posterior 

 margin for an Astrolampas, the phyllodes too short and too wide, 

 and the peristome is oblique, not regular. Lambert evidently did not 

 know that the peristome was oblique. In his description he states 

 that in most of the specimens he examined the peristome was cov- 

 ered with matrix, and that it appeared to be pentagonal. If he had 

 known that the peristome was oblique, he certainly would not have 



