58 Proceedings of the Biological Society of Washington. 



it, there is a series of tliree much smaller and shorter spines, not greatly 

 larger than the granular spines of the actinal intermediate plates, from 

 which they are separated by a narrrow bare area. 



The mouth plates have seven stout spines on the furrow border, which 

 decrease very slightly in length ; within the distal portion of the furrow 

 border are two much stouter spines, and just within the apex another 

 similar to these; along the inner margin of the plates is a row of five or 

 six spines similar to these, but shorter. 



Type.— Gat. No. 38,318, U. S. N. M., from the west coast of Mexico. 



Family LINCKIID^ Perkier. 

 Narcissia gracilis new species. 



Five arms; R=54 mm.; r=8.6 mm. ; R:r=6.3:l; height to apex of 

 abactinal region 7 mm. ; width of arms at base 10 mm. 



General form stellate, with long slender regularly tapering rays, up- 

 turned at the tip ; the body is low, the maximum height being less than 

 the diameter of the arms at their base ; the arm section at the base is 

 low, rounded triangular. 



The center of the abactinal surface is occupied by a mass of plates of 

 different sizes in which the primary plates can usually be distinguished. 

 From this central mass of plates there runs down the mid-line of each of 

 the arms a prominent series of elongate polygonal plates bordered on 

 either side by a row of much smaller plates beyond which is another row 

 of larger plates, which are nearly as large as the plates in the mid-radial 

 series. At the middle of the arm the series of small plates on either side 

 of the carinal series disappears, and the carinal series merges with the 

 large plates of the series beyond, the three series combining to form a 

 broad dorsal band of irregularly arranged subequal polygonal plates. 



In the proximal half of the arm many, or most, of the plates in the 

 carinal row and in the rows of larger plates on either side of it bear 

 pedicellariae, but these are absent in the outer half of the arm. 



Between the rows of large plates on either side of the carinal series in 

 the proximal half of the arm and the dorsal band of large plates in the 

 distal half of the arm, and the superomarginals, there are five rows of 

 plates decreasing very slowly in size from above (abactinally) downward; 

 of these rows the lowest reaches only to the third-fifth superomarginal, 

 the second reaches to the fifth-eighth, and the third reaches the eighth- 

 twelfth; the fourth and fifth, distally becoming more or less irregular, 

 persist nearly to the tip of the arm. The last thirteen-fifteen supero- 

 marginals are in contact with the mid-dorsal band of large plates. 



The madreporite is small, circular, 1.5 mm. in diameter, situated mid- 

 way between the center of the dorsal surface and the interbrachial angle. 



The anus is rather prominent, excentric, protected by short stout 

 spines. 



Single papulse occur in the angles between all the abactinal plates, ex- 

 cepting between the plates in the broad dorsal band in the distal half of 

 the arm, where they are rare. There are no actinal papulae. 



