LUCERNARI^ANDTIIEin ALLIES. 37 



in the cliondrvmyophix, or in another locality it is on the opposite face of the latter 

 or it is buried in the solid mass of the dioiulmplii/x. If we trace it now tlirou<T;h all 

 its windings and variations of form we shall meet with the following subdivisions. 



79. Ill the proboscis {figs. 47'', 53, m*^) it is a very thin, uniform layer which, on 

 the one hand, lies against the posterior face of the opsophragma (/*'), and on the 

 other, overlies the chondromyoplax (//). It commences abruptly at the edge (p^) 

 of the mouth, in the angle just at the line of junction between the opsopliragma 

 (n'') and the gastrophragma («'), and follows all the curves, vnidulations, and 

 Avrinkles of the manubrium, marking its way by numerous, delicate, longitudinal 

 striations. It requires a magnifying power of at least two hundred diameters to 

 determine that these striations arc fihrllhr,, and that they are not to be confounded 

 with the heavier strite and ribbon-like elements of the umbella proper, which can 

 be seen with a very low amplification. Their nearest homologues are to be found 

 in the tentacles and anchors, but the relations of the two are not altogether iden- 

 tical, since the fibrillje of the latter do not form a continuous stratum like that in 

 the proboscis. It is but just to say that a similar striation is discernible in all 

 parts of this system ; but we must observe that in the manubrium it is the only 

 marked feature of organization, whereas in the umbella and the peduncle it is the 

 arrangement of these features in folds, columns, etc., which, in the most conspicu- 

 ous manner, indicate to the eye the site of the muscular subdivisions of the body. 



80. Muscles in the umhella. — Beyond the limits of the proboscis the system is 

 differentiated in such a decided, methodical manner as to form a prominent guide, 

 among a few others, in localizing the surrounding organs and the specially endowed 

 regions. It continues from the proboscis to the margin of the umbella without 

 changing its position relatively to tlie opsophragma, but although still lying in 

 front of the chondromyoplax, it is somewhat altered in conformation and in its 

 connections with the latter layer. It will be observed in our figures {figs. 22, 37, 

 50, m) that a coarse kind of striae pervades the anterior parietes of the umbella, 

 but that it is not uniform in quality, and seems to be divided into two sets of four 

 subdivisions each, alternating with one another. In the four areas which overlie 

 the middle of the four umbellar camerae the striation is simple, and extends from 

 the proboscidial buttresses (i,'') with a wide flabelliforra divergence, and merges 

 gradually into a moderately broad, marginal band {m^) of strong parallel stria?. 

 Immediately over the eight genital halves (X) this quality of striation is absent, 

 and is replaced by the finer kind, only discernible, as in the proboscis, with a 

 comparatively high power. 



81. In the space included between the halves of each genital, and lying collateral 

 to the partitions (ij--), we find the most evident expressions of strength and solidity 

 to be met with in any part or organ of the body, excepting the peduncle. The 

 striation here possesses more of the character, in appearance, of a banded surface, 

 owing to the regular distances apart at which the stria? are disposed. They have 

 a pennate rather than a fiabelliform arrangement, but so situated, tliat, altliough 

 they diverge from each side of tlie partitions along the whole length of the latter, 

 they all tend obliquely to the margin (a|.^) of the umbella, and there rini gradually 

 into those groups of deeply marked stria? which run, like a band (//(') along the 



