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BULLETIN OF THE BUREAU OF FISHERIES. 



acted upon by McMurrich (vide supra), who proposed its reference to the genus Eloactis of Andres. 

 This was later followed by Parker, and following these proposals I have formally accepted this refer- 

 ence. At the same time it should be said that the grounds of the proposed reference to another gentis 

 are not altogether conclusive. Whether a given species be hexamerous or decamerous, in view of 

 the range of variation now known to prevail to considerable e.\tent, can hardly be of great significance 

 as a taxonomic feature. While the species under consideration is apparently prcdominently decam- 

 erous, I have fotind considerable variation in this respect. In younger specimens the hexamerous 

 condition is not at all uncommon. In several different specimens some 50 to 70 mm. in length which 

 I took occasion to section and examine the hexamerous state was prevalent. In very large specimens 

 the decamerous arrangement was quite as prevalent. 



The general features of the species will be fairly well shown in figure 4, plate XLii. As will be 

 seen, the body is elongated, more or less cylindrical, and comprises some three distinguishable regions: 



An oral, retractile portion, or capitulum; a 

 basal, bulbous portion, or pedal-like disk, 

 or physa; and an intermediate portion, the 

 column. This is marked by a series of 

 about 20 longitudinal grooves, whose inter- 

 mediate ridges are provided with numerous 

 papilliform suckers, by means of which the 

 creature is able to retain itself in the burrow. 

 The length of the body varies greatly, aver- 

 aging perhaps 100 to 150 mm. in ordinary 

 life. In some cases at full extension it may 

 become twice this length (Verrill). The 

 diameter also varies greatly. It probably 

 averages about 8 to 10 mm. The tentacles 

 are normally 20 in number, with occasional 

 variations, rather stout, with brownish knob- 

 like tips. The color varies from whitish to 

 pale salmon on the column, the base trans- 

 lucent, with bluish tint. A white variety 

 has been described under the name Hal- 

 campa alhida; but this is doubtless a merely 

 varietal character, and in nowise entitled to 

 specific distinction. 



Habitat: The species is characterized in 

 a remarkable degree by the burrowing habit. 

 In many years of observation I have never 

 found it except in burrows on sand flats 

 between tide lines. In this habitat it forms burrows wherein it lives, perhaps more or less perma- 

 nently. However, it should be said that specimens in the aquarium, in which, by the way, it will 

 thrive for weeks in apparent vigor, yet show a tendency to emerge from tlie burrows at night and to 

 migrate variously about the aquarium. A further fact may not be without some significance to the 

 same effect, namely, that its burrows do not become lined by a tubular product, such as is provided 

 by Cerianihus. I have elsewhere (Biological Bulletin, vol. xii, p. 274) pointed out certain peculiarities 

 of behavior of some significance in this connection, and also as indicating something as to modes of 

 life. That it is markedly sensitive to varying degrees of light, even to the extent of distinguishing 

 between light and darkness, which has rendered the species predominantly nocturnal, seems to be 

 beyond doubt. 



These two features, namely, the burrowing and nocturnal habits, conspire to render its presence 

 unknown by most people, except those who especially direct attention to its discovery. While more 

 abundant locally than either Sagartia modesta or Edwardsia elegans it is yet far from common. 



-Tealia crassicornis. Section of circular muscle (c. m.); 

 entoderm; m, mesoderm; cc, ectoderm. 



