REPOET ON THE ECHINOIDEA. ' 123 



Echinolampas oviformis (PI. XXXVII. figs. 10, 11 ; PI. XXXIX. fig. 12; PI. XLI. 

 figs. 9, 10 ; PI. XLIII. figs. 3-5 ; PL XLIV. figs. 41-44). 



Echinus ovifortnis, Gmel., 1788, Linn. Syst. Nat. 

 Echinolampas oviformis, Gray, 1825, Ann. Phil., p. 7. 



I have figured on Plate XXXVII. the single specimen of Echinolampas collected by 

 the Challenger. It is interesting as it is still covered wdth spines, while nearly all the 

 specimens of which I have any knowledge are bleached and denuded of spines. The 

 spines are remarkably short over the whole of the abactinal surface, they are distant, 

 slightly swollen at the extremity, and the iutertubercular space between the primaries is 

 closely pack-ed by minute slender miliary spines. On the actinal surface the spines are 

 longer and more slender, the miliary spines less numerous ; the spines increase in length 

 towards' the actinostome and form quite prominent tufts of larger spines over the 

 bourrelets and in the interambulacral spaces adjoining the actinostome. 



The colour of the spines in alcoholic specimens is yeUowish-green. The general fades 

 of the spines and their arrangement on the test recalls more that of the Clypeastroids 

 (such groups as the ScuteUidse) than the Spatangoids proper. 



Station 192. September 26, 1874. Lat. 5° 42' S., long. 132° 25' E. ; 129 fathoms ; 

 mud. 



Cato^yygns. 



Catojjygws, Agassiz, 1836, Prod., p. 185. 

 *Catopygus recens (PI. XX. figs. 17-21). 



Gatopygus recens, A. Agassiz, 1879, Proc. Am. Acad., vol. xiv. p, 204. 



Seen from above (PI. XX. fig. 1 8) the test is ovoid, being broadest posteriorly; the apical 

 system is anterior, there are three genital pores, the left anterior l^eing wanting ; the 

 madreporic body is indistinct. In the petaloid ambulacra the exterior pores are comma- 

 shaped, the interior circular. All the petals are similar in structure, and the anterior 

 and posterior ambulacral petals are equal in length, while the odd anterior is somewhat 

 longer. The median posterior interambulacral suture is sunk in a shallow groove 

 (PI. XX. fig. 18), which gradually deepens towards" the anal system, beyond which 

 it becomes quite deep (PI. XX. fig. 20) and then gTadually comes to the surface of 

 the test at the angle of the round beak, forming the extremity of the anal plastron as 

 is well seen in the end view of the test (PL XX. fig. 20). The summit of the test 

 corresponds with the apical .system (PL XX. fig. 21), the posterior edge of the test is 

 regularly rounded, the anterior extremity forming a rounded point by the junction of 

 the actinal and abactinal curves of the test, where they unite below the extremity of the 

 odd anterior petal. Seen from the end the outline is heart-shaped (PL XX. fig. 20) with 

 the rounded anal beak projecting below the level of the actinal surface. The actinal 

 surface is gibbous, with a nearly central sHghtly sunken actinostome, the phyllodes 



