40 Chirk — Two New Australian Crinoids. 



Disk and brachial ambulacra naked; coveri)io: and side plates well 

 developed in the distal half of the pinnule ambulacra. 



Ends of the basal rays visible as rliondjie tul)ercles in the angles of the 

 calyx, but not projecting above the general surface of the radials; radials 

 rather prominent, nearly four times as broad as long, gently concave 

 anteriorly; i Brj about twice and one-half as broad as long, the straight 

 lateral edges in ajiposition ; i Br, (axillary) rhoml)ic, al)out twice as broad 

 as long, the lateral edges about one-half as long as those of tlie i Br^ ; 

 II Br 2, in the type developed on the right side of three of the i Br series, 

 on both sides of one of the i Br series, but absent from the fifth i Br 

 series. Division series and first two brachials exteriorly with a uniformly 

 produced narrow border, by which they are in lateral apposition, though 

 they are not laterally flattened. 



Arms 15 in number (in tlie type) about 55 mm. long; brachials in 

 general as in P. macronema, l)ut sharjily rounded dorsally in the distal 

 half of the arm instead of sharply cariuate, the long overlapping spines 

 of that species being represented by insignificant tubercles on the median 

 part of the distal edge of each joint. Syzygies occur between the third 

 and fourth brachials, again between the twelfth and thirteenth or 

 thirteenth and fourteentli, and distally at intervals of five to seven ( usually 

 six or seven) oblique muscular articulations. 



Pj 8 mm. long, stiff, ratlier small, with nine joints, the first not quite 

 so long as broad, the second slightly longer than broad, the third twice 

 as long as its proximal diameter, the remainder greatly elongated, except 

 for the minute terminal joint; Pj 12 mm. long, much stouter than Pj, 

 with nine joints, similar in proi)ortion to those of Pj ; Pg the longest on 

 the arm, 13 mm. or 14 mm. long, with eleven joints, of similar propor- 

 tions to those of the two preceding pinnules; P4 11 nun. long (intermedi- 

 ate in length between Pj and P2), with eleven or twelve joints, the first 

 twice as l)road as long, the second squarisli, the following gradually 

 increasing in length, becoming greatly elongated distally ; succeeding pin- 

 nules similar to about the middle of the arm, then becoming more slender, 

 slightly less stiff, and decreasing in length distally to about 9 mm. Pj 

 is occasionally absent, in which case P.^ is much smaller than usual. 



Color (in spirits). — Dull purple. 



Type locality. — Turtle Bay ancliorage, north coast of Dirk Hartog 

 Island, west Australia; 7 fathoms. 



Rt'markft. — Pfitomrtra dorcadis is very easily distinguished from /'. 

 macronema of the eastern coast of Australia by the very long cirri which 

 are much stouter l)asally, the proportionately much greater length of the 

 lower pinnules which are longer than, instead of shorter than, the distal, 

 and esi)ecially by the large size of P.^ and the elongation of the joints in 

 all the pinnules, these never l)eingso long as wide in /'. macronema, even 

 distally. The absence; of dorsal carination and of oviTlajiping sj>ines on 

 the brachials gives the arms a somewhat (Htferent appearance. Its 

 remarkal)ly robust aspect difterentiates it from P. macronema in about 

 the same degree that that species is difl'erentiated from P. trichopoda anil 

 P. pulcherrima of the Philippine Islands. 



