KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 7. 45 



conspicuously large pores. The pedicels belonging to this region may be called phyllo- 

 dean pedicels. In all the species examined the tubular shaft of" these pedicels termi- 

 nally expands into a circular convex disk, which, in the great majority, bears numerous 

 capitate tilaments covering its whole surface, PL VIII, jig. 64. They are disposed in 

 concentric circles, and longer and more closely set at the margin, slightly shorter to- 

 wards the centre, thus forming, with their tumid tops, almost a section of a sphere. 

 Each filament contains a prolongation of the clear and homogeneous layer of the tube, 

 and, imbedded in it, a slightly arched calcareous rod, by which the filament is kept 

 rigid and in supination, PL VI II, jig. Jo, 56, 38, 60. This rod, in the great majority of 

 species, rises more or less centrall}' from a circular basis of areolar texture, in its imma- 

 ture state not unlike the wheels so frequent in Holothuria^, PL XI, jig. 121. On its 

 under side it presents a prominent nave, PL VllI, jig. 63, while on the upper side a 

 number of its fibres unite in forming the rod, which in some species is linear, in others 

 at first contracted, then in most cases slightly widening, again attenuated and obtuse 

 at the top, sometimes faintly clavate; dense and smooth, as in Brissopsis, Schizaster, 

 Echinocardium, or presenting internal ti-aces of meshy texture PL VIII jig- 59, 60, 

 and a rough, even spiny surface, as in Meoma, Lovenia, Spatangus. In Urechinus 

 Naresianus, jig. 56, the rods are rather strong, not solid, but areolate throughout. 

 Generally the conformation of the I'ods resembles a simplified miniature of that of a 

 spine or radiole. 



On the structure of the tumid tops of the filaments in Brissopsis lyrifera, I 

 formerly made some observations, PL IX, jig. 80, 81, 82. From a thin layer, a plexus 

 surrounding the homogeneous central substance, numerous nervous fibres are seen to 

 traverse the connective tissue towards the inside of the external tegument, and there 

 to form nucleated multipolar cells in close proximity and connexion with the bases 

 of very minute, scattered, rigid and motionless hair-like processes on the external sur- 

 face, which is devoid of vibratile cilia. From this structure the tactual function of 

 the phyllodean pedicels appears to be fully confirmed; I give it here with a view of 

 inducing further research, and at the same time will draw attention to the peculiar 

 forni of the tops of the filaments in Metalia, Lovenia and others, observed in Speci- 

 mens too long preserved in spirits to bear with a closer examination, PL VIII, Jig. 

 61, 62. 



From this description of the phyllodean pedicels, as I have observed them in 

 the greater number of known genera, only three of these have presented exceptions, 

 possibly more apparent than real. In Aceste bellidifera Wyv. Thoms., PL VIII, jig. 

 67, 68, which in some of its characteristics shows a certain analogy to Schizaster and 

 Moira, even in the strangely forward position of the oesophageal opening, — an ex- 

 aggeration of a feature not altogether foreign to tliera, — I found the disks of the 

 phyllodean pedicels croAvned only Avith a double marginal circle of filaments, leaving 

 the central part naked, and raised into a high, rounded protuberance, Avhich, when seen 

 from above, presents distinct traces of five converging plicatures. Palteostoraa rairabile 

 Gray pi-esented forms very similar, PL XVI, jg. 192, 193. In Palaeotropus Josephina? n. 

 were found, among the regular phyllodean pedicels, some, jig. 72, that presented the 



