8 LUCERxNARI^ AND THEIR ALLIES. 



offcriiii? a new view of the typical relations of the organism were then given in a 

 brief sketch ; too brief in fact to suffice for our present purposes In this place, 

 however, we shall only state our position in regard to the matter, and refer to 

 those chapters (Part XV) which are especially set apart for the discussion of the 



question. 



17. We assume that, as in all the otlier four grand divisions of animals, the 

 moutli is at the cephalic or anterior extremity of the body, and that all the rest of 

 the organism is virtually, if not really, topographically behind it, and that what- 

 ever extends from the oral end of the body does not radiate from that end in two 

 three, four, or five, or more directions, but trends posteriorly in so many lines 

 parallel-wise to a longitudinal axis, and to a vertical sectant plane which divides 

 the body into a bilateral figure. To give the idea a reality, Ave liave but to 

 point to the mouth of an Actinia as the cephalic end of our bilateral figure, and 

 looking inwardly we shall see tlie flat stomach forming the sectant plane, which, 

 extended in imagination, in two opposite directions, would strike the periphery of 

 the body along two dorsal and ventral lines one hundred and eighty degrees from 

 each other, and then, projected still further away from the mouth, would terminate 

 finally in the posterior, adherent, discoid end. Parallel-wise with this plane all of 

 the partitions of the digestive cavity trend, like a series of superposed shelves or 

 galleries, in direct lines from the region lying right and left of the mouth, and of 

 tlie flattened parallel sides of the stomacli, backward along the inner face of the 

 cylindrical periphery, so as to subdivide the included space into as many longi- 

 tudinal corridors. It is tliese partitions Avliich, by their multiplied sameness, 

 constitute, among otlicrs, the elements that eud)ody the dorso-veiitralhj rejjetltire 

 type ; the true ideal, as we fully believe, upon which this grand division is 

 founded. 



18. AVe think we shall be understood now, Avhen we say that the multitudinous 

 chymiferous canals of the disciform ^Equorea and the quadruple channels of the 

 cylindrical bell of Sarsia are two widely separated extremes of dorso-ventrally 

 repetitive sameness ; or that the numerous ambulacra of SoJaster and the five of 

 Asterias represent two extremes of dorso-ventral repetition, thrown forward, " into 

 rank," to the same line with the mouth ; Avhilst the retreating rows of Echinus, 

 and the more diff'erentiatcd ones of Spafangus and Schizasler, and the like, present 

 the idea in a less disguised form, to be finally exemplified, in its fullest expres- 

 sion and clearness, in the elongated, vermiform Eolofhurice. 



19. The reader, probably, will not fail to comprehend us then when we state 

 that the proboscis of a Lucernarian lies at the anterior end of the body ; that the 

 region of the main cavity-, the umbelliform part of this creature, is a great deal 

 wider than it is long, Cc, it is extremely foreshortened (no more diflicult to 

 conceive, we take it, than that the short, globose body of an Octopus or a Cirrhoteu- 

 this is a foreshortening of the same typical elements that exist in the extremely 

 elongated, slender body of a Loligopsis) ; and that the so-called peduncle forms a 

 thick, cylmdrical, caudal termination at that end of the longitudinal axis which 

 lies most distant from the one where the mouth opens. Finally, we will add, that 

 the lateral halves of the body lie right and left of a plane which passes through 



