BALANOGLOSSIDA. 103 



Willey, bimmiensis Willey, jamaicensis Willey. Glossobalanus Speng., gill 

 apertures as in. Balanoglossus, genital pleurae reduced to ridges, Gl. minutus 

 Kow., sarniensis Koehler, hedleyi Hill, ruficollis Willey. 



Fam. 2. Glandicipitidae. Proboscis longer than collar. Notochord fre- 

 quently produced anteriorly into a vermiform process. Cornua of proboscis 

 skeleton extend to posterior region of collar. Nerve -roots absent or vestigial. 

 Efferent vessels of proboscis pass obliquely downwards to posterior end of 

 collar. Peripharyngeal spaces separate, vestigial or absent. Perihaemal 

 cavities contain transverse muscles. Circular muscles of body-wall lie 

 inside the longitudinal muscles. Genital pleurae and lateral septa of 

 trunk coelom absent. External liver saccules present or absent. 

 Schizocardium Speng., right and left peripharyngeal cavities and synap- 

 ticula present, ventral septum of proboscis extends to end of vermiform 

 process, external liver saccules present, medial gonads absent, pericardial 

 auricles highly developed, hypopharyngeal streak of pharynx reduced to 

 narrow band (Fig. 63) ; Sch. brasiliense and peruvianum Speng. Spen- 

 gelia Willey, peripharyngeal cavities and synapticula as in Schizocardium, 

 ventral septum of proboscis does not extend to the vermiform process, 

 external liver saccules absent, medial gonads present or absent, pericardial 

 auricles reduced (Fig. 64), dermal pits in the genital region, hypopharyngeal 

 groove deep and well marked as in Ptychodera ; Sp. porosa and alba Willey. 

 Glandiceps Speng., peripharyngeal cavities and synapticula absent, ventral 

 septum of proboscis and external liver saccules and medial gonads as in 

 Sp., pericardial auricles reduced, hypopharyngeal streak of pharynx re- 

 duced to broad tract (Fig. 63) ; G. talaboti and hacksi Marion, G. abyssicola 

 Speng. Willeyia Punnett, branchial part of pharynx small compared with 

 ventral portion, without dermal pits, synapticula, medial gonads. 



Fam. 3. Harrimaniidae. Boreal forms with large eggs and direct 

 development, vermiform process of notochord and dorsal roots of medul- 

 lary cord absent ; cornua of proboscis skeleton, efferent vessels of proboscis 

 and perihaemal cavities as in Glandicipitidae ; perihaemal spaces present 

 or absent ; no circular muscles in body-wall of trunk ; synapticula and 

 external liver saccules absent. Harrimania Hitter, proboscis short, 

 proboscis pores paired, peripharyngeal spaces absent, medial gonads 

 present ; H. kupfferi v. Will.-Suhm ; H. maculosa Ritter. Dolicho- 

 glossus j Speng., proboscis long, proboscis pore unpaired, peripharyngeal 

 spaces present, medial gonads absent ; D. kowalevskii A. Ag., D. 

 mereschkowskii N. Wag., D. sulcatus * Spengel, with a dorsally grooved 

 proboscis and 10 or 11 pairs of gill-slits; D. ruber Tattersall, from 

 west coast of Ireland. Stereobalanus Speng., proboscis short, two 

 proboscis pores, two pairs of genital pleurae. 



Fam. 4. Protobalanidae.t The coelom preserves its primitive arrange- 

 ment, is free from mesenchyme and its mesenteries persist. Lateral septa 

 are absent from the trunk, and perihaemal and peripharyngeal cavities 

 from the collar. Gonads in a single row. The other characters as in the 

 Harrimaniidae. Protobalanus Caullery and Mesnil, P. koehleri, 4-6 cm. 

 in length, St. Martin's Bay, Cap de la Hague, north coast of France. 



* Dolichoglossus otagoensis Benham (Q.J.M.S., 42, 1899, p. 497), a form 

 recently described from New Zealand, creeps on seaweed by means of 

 a very contractile proboscis, which is grooved dorsally as in D. sulcatus ; 

 it possesses only 12 pairs of gill-slits. 



f Caullery et Mesnil, Zool Jahrb. Anat., 20, 1904, p. 227. 



