CALKINS: SOME HYDROIDS FROM PUGET SOUND. 341 
one. Of the remainder, the Haleciidae is the most primitive of the 
thecate forms and with the closest athecate connections, as shown 
by the method of branching (see Driesch, ’90) and the nature of 
the hydrotheca so-called. It was shown by Levinsen that the 
Coppinidae (with Hincks only a single species) are only gonothecae 
of species of the genera Lafoea, Filellum, and Grammaria (Mark- 
tanner-Turn eretscher) . 
The Sertulariidae and Plumulariidae are retained as well-marked 
families, although Levinsen apparently takes a backward step in 
splitting the latter into two families, Plumulariidae and Aglaophe - 
niidae. 
These eight families including all of the true thecate hydroids are 
thus reduced to four and may be arranged in the following order: 
Haleciidae , Campanulariidae , )Sertulariidae , and Plumulariidae . 
Haleciidae. 
The Haleciidae are usually regarded as one of the most highly 
differentiated forms of thecates because of the small cups, the 
incomplete retraction of the hydranth, and the peculiarity of the 
gonophores in that the blastostyle protrudes beyond the gonotheea 
and then gives rise to one or two hydranths. Levinsen (’93) 
showed the close connection between Haleciidae and Campanula¬ 
riidae in the presence of stalked hydrothecae, lack of opercular 
apparatus, and circular mouth. He also found a ring of peculiar 
chitinous particles about the lower and wider part of the hydranth 
by means of which the hydranth is fastened to the cup, the same 
thing, he says, being characteristic of the Campanulariidae. 
According to Levinsen a still closer connection is with the 
Plumulariidae, shown primarily by the shallow and wide beakers or 
cups, which have a well-developed diaphragm; the chief differential, 
he thinks, in distinguishing the Campanularians. In addition to 
this character the incomplete retraction of the hydranth and the 
occasional occurrence of nematophores on some Haleciidae are 
features common to the two families. 
Schneider (’97) admits the close relationship of Campanulariidae, 
Llaleciidae, and Plumulariidae, but points out. that Levinsen gives no 
clue to the origin of the Haleciidae. Tie says these forms cannot be 
derived from the Campanulariidae, 1, because the branched Llale- 
