Polyzoa of the St. Lawrence. 219 



and Smitt, and it might almost seem superfluous to discuss it 

 further. But Sars's account is unaccompanied by figures, 

 and is so far unsatisfactory. Smitt has supplied this defi- 

 ciency, and would have left little to be desired if his figures 

 had been drawn on a larger scale. The difiiculties of the 

 Swedish language may probably prove a more serious obstacle 

 to the student, and it may not therefore be useless to give a 

 brief account of the development of the zooeciura. 



It would be a waste of time to consider whether Lam- 

 ouroux's Eschara lobata {' Exposition Mdthodique ') was 

 founded on the present form. It may have been ; but neither 

 his description nor his figure affords the means of settling 

 the question with certainty. It is only an adequate diagno- 

 sis or figure that gives to any name a claim to adoption, and 

 it must be accounted an injury to science to burden its records 

 with merely speculative identifications. 



Prof. Verrill refers Lepralia prodiicia of Packard to this 

 species ; but unless he had the opportunity of examining an 

 authenticated specimen he would find it difficult, 1 think, to 

 prove his point. Packard's description, even when supple- 

 mented by his figure, is quite inadequate. 



The changes which the zooecium passes through in this 

 species are very striking, and show in a very forcible way 

 the necessity of a careful study of the Polyzoan colony 

 through all the phases of its growth. 



The young marginal cell presents a smooth or slightly 

 wrinkled surface, perforated round the edge. 



The orifice is suborbicular, perfectly simple, and not ele- 

 vated above the cell-wall (PI. XIV. tig. 1 a). In this stage 

 the cells are convex and the sutures well defined. 



The first change consists in a slight sinuation of the lower 

 margin of the orifice, which is accompanied by an elevation 

 of the peristome. In the second row (from the margin of the 

 colony) a rather deep and somewhat irregularly shaped sinus 

 has been developed, bounded by two denticular processes 

 (PI. XIV. fig. 1 h), within which an avicularium has origin- 

 ated, the mandibular portion of which is placed obliquely 

 along one side of the sinus, whilst the avicularian chamber 

 (a pouch-like inflation of the surface) lies between it and the 



posed, as it seems to me, of somewhat heterogeneous elements. Veriill 

 has dismembered it acd retains the name Discojxira for forms " having 

 both median and lateral aviculai'?*^ with the former (or both) often raised 

 on a prominence in front of the zorecial aperture" (Proc. U. 8. Nat. Mus.). 

 These changes cannot be discussed here, but I see no reason for merging 

 the genns Esc/iaroides in any other group. 



