REPORT ON THE CRINOIDEA. 117 



described ; though traces of it are apparent in Antedon breviradia (PL III. fig. 4b). 

 Only a few fragments of the arms are preserved, and no traces of sacculi are visible in 

 the broken pinnules which I have been able to examine. 



11. Antedon multispina, n. sp. (PI. XIII. figs. 1-3; PI. XIV. figs. 5-7; PI. LXIX. 

 figs. 1-4). 



Specific formula — A. ( 3 - 9 ) -y- 



Centro-dorsal hemispherical, bearing about twenty cirri of twenty-five to thirty joints, 

 a few of which are longer than wide. The remainder are shorter and overlap slightly 

 so as to develop a dorsal spine. 



First radials invisible in the adult ; second very short (in the adult) and axillaries 

 widely pentagonal. The axillaries and first brachials have flattened outer sides and 

 straight edges ; and the inner sides of the second and hypozygals of the third brachials 

 are also flattened. Numbers of small spines on the calyx and arm-bases. 



Usually ten arms, but one individual has two tridistichate series. Arm-joints 

 elongately quadrate, with tufts of numerous small spines at one or both ends. The first 

 pair of brachials borne on the distichal axillary are united by syzygy ; but above the 

 radial axillaries the third brachial is a syzygy, the next between the ninth and fifteenth, 

 and others at intervals of three or four joints. 



The second brachial bears a pinnule of about twenty-five joints, the lowest of which 

 are wide, with their inner edges cut away a little and the outer sides slightly flattened. 

 The next pair of pinnules are much smaller, and the following ones gradually increase in 

 length, with the lower joints at first broadly V-shaped, but afterwards more elongated. 



Disk and arms well plated. Side plates fairly developed on the pinnule-ambulacra, 

 with moderately abundant sacculi. 



Colour in spirit, — -light brownish-white. 



Disk 4 mm.; spread probably about 10 cm. 



Loccdity. — Station 344, April 3, 1876 ; near Ascension ; lat. 7° 54' 20" S., long. 

 14° 28' 20" W.; 420 fathoms; volcanic sand. Four broken individuals and three 

 Pentacrinoid larvae. 



Remarks. — This species has perplexed me a good deal, on account of the mutilated 

 condition of the specimens, three of which are quite immature, while the fourth, which is 

 apparently full grown, has twelve arms owing to the presence of two tridistichate series 

 (PL LXIX. figs. 1,2). I was at first inclined to regard it as a small variety of Antedon 

 porrecta (PL LII. fig. 3) which occurs at the same station. But the tridistichate 

 character is the only resemblance between the two forms, their cirri, arms, and pinnules 

 being altogether different; and I am therefore forced to conclude, as with Antedon 



