338 BULLETIN 76, UNITED STATES NATIONAL MUSEUM. 



Sarlcaster validus Ludwig" ranges from the Galapagos to the Tres Marias Islands 

 and from 680 to 28G fathoms. There are no important differences between this 

 species and the A^ariablc Lophaster furcilliger. The type of furcilliger happens to be 

 from deeper water than validus, and has more delicate paxillse and spines generally. 

 The Alaskan exami)les of furciUigcr from lesser depths are nearer validus, having 

 the inferomarginals larger than the superomarginals, lower paxillse, and stouter 

 rays. Although Ludwig's excellent description and figures seem to indicate slight 

 differences, these are more than compensated by the variations of the specimens 

 at my dis|)osal. The Alaskan specimens of furcilliger are quite as distinct as is 

 validus but if one started to name the intergrading forms with vexator there would 

 be no end. 



LOPHASTER FURCILLIGER VEXATOR Fisher. 



PI. 80, figs. 1, 2; pi. 114, figs. 2, 2a. 

 Lophaste-T furcilliger vexator Fisher, Zool. Anz., vol. 35, March 29, 1910, p. 574. 



Diagnosis. — Similar to L. furcilliger, but with larger disk, thicker rays, much 

 stouter paxilliTB both abactinal and marginal, and with stouter abactinal spinelets 

 having six to ten points instead of two to four, heavier adambulacral spines, and 

 more closely placed adambulacral plates. Perhaps intermediate between L.furdfer 

 and L. furcilliger. Type, R = 89 mm.; r = 27 mm.; R = 3.3 r. Breadth of ray at 

 base, 30 mm., or about one-third R. 



Description. — This form, variety, race, or small species stands near to furrilliger 

 although the extremes are decidedly different in appearance. Vexator is a much 

 stouter animal with thicker rays, more robust paxillse, and stouter skeletal parts, 

 due possibly to the shallower habitat. In furcilliger the pedicels of paxillse are 

 decidedly slender and the spinelets are about a half to two-thirds the extreme 

 length of pedicel. The spinelets are very delicate and glassy with two or three 

 extremely sharp points at the flaring tip (sometimes four), and commonly one or 

 two series of perforations along the middle of the spinelet. But in typical vexator 

 the pedicels are shorter and stouter, and the spinelets are about the same length as 

 in fircilliger or shorter, ending in six to ten points distributed along the outer 

 third or half of the spinelet. There are also several rows of perforations along the 

 center of spmelet where the wing-like expansions or buttresses which terminate in 

 points join to form the core of the spinelet. The abactinal plates or bases of paxillse 

 are of the same general structure as in furcilliger, but usually stouter. Papulae in 

 type and large examples ten to twenty-five to an area on disk and midradial region, 

 laterally five or six. Proximally they sometimes encroach upon the marginals and 

 lie intra-marginally, but this is not usual and occurs only in very large specimens 

 such as the type. 



Marginal plates very robust, the inferomarginal paxillse stouter than supero- 

 marginal and compressed toward the end in large examples. The difference in 

 size between the marginal paxillse in typical furcilliger is slight or not marked and 

 the inferomarginals are not compressed at the tip. The marginal spinelets are 

 variable in length, but usually shorter, stouter, and more dentate than in /wmZZi^er. 



Adambulacral plates with the furrow combs typically nearer together than in 

 furcilliger, but some specimens having them slightly spaced and hence interme- 



o 1905, p. 185, pi. 15, figs. 75, 76; pi. 29, figs. 171-173; pi. 30, figs. 174-177. 



